Turret locking mechanism



March 18, 1947. c. E. MILLER 2,417,505

TUBREEF LOCKING MECHANISM Filed 001. 27, 1944 17 I v p j] g II W I W Q i f j W Patented Mar. 18, 1947 TURRET LOCKING MECHANISM Carroll E. Miller, Windsor, Vt., assignor to Cone Automatic Machine Company Inc., Windsor,

Vt., a corporation of Vermont i Application October 27, 1944, Serial No. 560,691

1 Claim.

This invention relates to locking mechanism for-indexing turrets, such for example, as those employed for carrying the work holding spindles v of'multiple spindle lathes and screw machines, though the invention in its broader aspects is not restricted thereto. Such turrets, particularly in multiple spindle lathes and screw machines of the larger sizes, are of considerable weight,.and their inertia forces during indexing correspondingly large. Secure locking of such turrets between indexing operations has heretofore:resulted in considerable shock and noise, and shorts to lessen these objections have usually resulted in a less secure'locking action.

The present inventionhas for an object, therefore, to decrease the noise and shock of the locking action, while-at the same time to insure that this locking action is secure. Tothese ends, the locking mechanism, in accordance with the present invention, is snapped to aniinitial locking position under arelatively light spring-action, thus reducing "the noise and shock, and it is immediately thereafter forced under increased yieldingjpressureinto fulllocking position and there held until'such time as it is desired to unlock the turret for indexing. The increased pressure'may be provided by loadingthe spring or springs by which the initial locking action is produced and the unlocking may be so accomplished as to remove the heavy locking pressure suddenly, producing an initial loosening shock to the locking mechanism and thereafter to fully release the locking mechanism against relatively light spring pressure.

For a more complete understanding of this invention, reference may be had to the accompanying drawings in which Figure 1 is a fragmentary transverse vertical sectional view on line II of Figure 2 of a multiple spindle lathe of the well known Cone type, embodying the invention, and showing the turret in locked position.

Figure 2 is a detail sectional view on line 2--2 of Figure 1.

Figure 3 is a top plan view of the locking spring loading device, its actuating cam being shown in section.

For the purpose of illustration, this invention is shown as applied to a multiple spindle lathe such as is illustrated in the Cone Patent No. 2,142,557. Such a machine includes a turret I carrying a plurality of work holding spindles indicated diagrammatically at 2 and indexable about a horizontal axis at 3. At points spaced angularly about the periphery of the indexing turret, are sockets, one of these being shown at 4;.inFigure 1, into which may be projecteda lockingbolt 5 when any of thesesockets comes into alinement with the locking bolt, the bolt then being projected into the socket and locking the turret against further indexing action until such time as the bolt is retracted, whereupon indexing maybe resumed. I

The locking bolt 5 is slidably guided between ways 5 for motion toward and from the. periphery of theturret, and as shown the bolt has a beveled face 'I at .its locking end to facilitate the entrance and withdrawal of the bolt from locking position. The bolt is normally pressed toward-the= periphery of the turretl so that it is in'position to snap into .a locking socket at the end vof-an indexing operation, and for this purpose. it, isshown as acted upon by"ispring means comprising avpair of 'coil. springs I0 reacting between an abutment plate II engaging the'top end of the locking-bolt .5. and an. abutment plate I2 engaging the oppositeends of these springs. The plate I2 is guided for motion lengthwise of a pairof guide rods I3 which extend through the ,coil springs II] .and into .the platell, and a pair of check nntsl lthreaded on the upperuends of the rods I3 limit the extent of motion of the plate I2 away from the plate II in a direction to lighten the pressure with which the springs I 0 act upon the locking bolt.

Means are provided for releasing the bolt from the turret for each indexing operation, and as shown this means comprises a cam I5 secured to a cam shaft I6 arranged horizontally and passing between the springs I0 and parallel to the indexing turret axis 3. This cam I5 bears against a follower I50 on a lever I! which is fulcrumed at I8 to a portion I9 of the machine frame. The inner end of the arm I! is provided with a finger portion 20 which engages in a slot 2| in the outer face of the bolt 5. The cam I5 is so shaped that in certain angular positions of the cam shaft I 6 it depresses the outer end of the arm I'I, lifting its inner end and retracting the locking bolt therewith.

Manually operated means may also be provided for releasing the locking bolt whenever this is desired. As shown this comprises a second cam 22 fulcrumed on the shaft I6 and provided with an actuating handle 23, as shown more particularly in the Cone Patent No. 2,142,557 to which reference has already been made.

When the turret reaches an index position, the bolt 5 is immediately snapped into one of the looking sockets 4 by the action of the springs II), but

at this time the springs in exert a relatively light force only thereon, since the plate I2 is then spaced a substantial distance from the plate ll. Immediately after this initial locking action has been produced, in accordance with this invention, the pressure exerted by the springs I is much increased, this being done by loading these springs by exerting downward pressure on the plate 12. For this purpose there bears against the upper face of the plate l2, a loading element comprising a bolt 25 adjustably threaded into an arm 26, this arm being fulcrumed on a cross pin 21 in a bracket 28 secured to the upper face of the frame portion 19 through which the cam shaft l6 extends and in which the shaft has a bearin in the bushing 33. The free end of the arm 26 is downwardly turned, and supports on a pivot pin 3|, a cam follower roll 32. This cam follower roll 32 rides against the face of an internal cam 33 secured to the endface of a cam drum 34 carried by the cam shaft IS. The inner face of the cam 33 is so shaped that just after the looking bolt has been projected by the unloaded springs III, the gradual incline 35 of the cam 33 engaging the follower roll 32, depresses this roll, consequently depressing the spring abutment plate 12 and applying a load to this spring. The cam follower roll 32 then continues to ride along a concentric surface portion 31 of the cam 33, retaining the increased load on the springs, thus holding the locking bolt firmly in locking position against the heavy spring pressure. Just. before the locking bolt is to be released, however, a sudden drop-off surface 38 of the cam 33 comes opposite to thecam roll 32, this suddenly allowing the roll to rise and release the loading. The sudden release of this loading causes the springs [0 to react suddenly with a shock which tends to jar the locking bolt loose from the socket in case it should have become stuck therein during the locking action, so that whenthereafter the cam l5 actuates the lock release lever, the locking bolt may be readily retracted out of locking position and release the turret for indexing. The loading pressure is put on thereafter only after the locking bolt has been projected for initially locking the turret at the end of the next indexing operation.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from the spirit or scope of this invention.

I claim:

In combination, a turret indexable about an axis and having angularly spaced sockets in its periphery, a locking bolt slidably guided for motion toward and from said periphery in position to be projected into said sockets serially and lock said turret in indexed positions, a pair of laterally spaced coil springs operatively bearing at one end against said bolt and tending to project said bolt, an abutment bearing against the opposite ends of said springs, means supporting said abutment for motion toward and from one end of each of said springs to thereby load and release load from said springs, a rotary shaft extending through the space between said springs, cam means actuated by said shaft for retracting said bolt against the pressure of said springs to release said turret for indexing and for permitting said springs to project said bolt to lock said turret when one of said sockets comes into registry with said bolt, a cam follower, a member carrying said follower and engaging said spring abutment, and an internal cam carried by said shaft cooperating with said follower and shaped to move said follower toward said one spring end to load said springs when said bolt is in projected turret looking position and to release such load when said bolt is about to be retracted.

CARROLL E. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,125,779 Waite Jan. 19, 1915 2,142,557 Cone Jan. 3, 1939 1,511,447 Drissner Oct. 14, 1924 1,735,898 Furber Nov. 19, 1929 

